Before you turn to any doc, it's good to knowÂ his/her credentials. Here's the scoop on a few:Â

Â Â Dr. Brown'sA staple of any good Jewish deli, the famous soda line started in 1869 with Dr. Brown's Celery Tonic, a seltzer fortified with sugar and celery seed extract. Early in the 20th century, other sodas weren't yet kosher, earning Doc Brown's line a permanent niche in places that served knishes.

Â Â Dr. Scholl'sWilliam Mathias Scholl was still a medical student when he invented the "Foot-Eazer" to correct arch problems. After becoming a podiatrist in 1904, he started his own company, which now markets everything from insoles to wart removers to medicated foot powder.

Â Â Dr. MartensSidelined by a skiing injury in 1945, German physician Dr. Klaus Maertens made himself air-cushioned shoe soles that allowed him to work despite his injured foot. Figuring he was on to something, he teamed up with Dr. Herbert Funck to mass-produce what started as a workingman's boot. The shoe's utilitarian purpose faded in the 1970s, though, when punk and goth musicians commandeered the brand and changed its image.

Â Â Dr PepperInvented in 1885, just one year before Coca-Cola, Pepper was the brainchild of Waco, TX pharmacist Charles Alderton. But it was Alderton's boss at the drugstore who got to name the drink, reportedly christening it after the father of a girl he fancied.